Subj : DAY1SVR: Day 1 Convective Outlook To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Sat Mar 04 2023 12:20:13 ACUS01 KWNS 041220 SWODY1 SPC AC 041218 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0618 AM CST Sat Mar 04 2023 Valid 041300Z - 051200Z ....NO SEVERE THUNDERSTORM AREAS FORECAST... ....SUMMARY... Isolated to scattered thunderstorms will be possible today across parts of the western U.S. and in north-central Florida, but no severe threat is expected. ....Synopsis/Discussion... In mid/upper levels, a low-amplitude, nearly zonal, shortwave- dominated pattern is expected over the central/eastern CONUS, downstream from an amplifying area of cyclonic flow over the West. The eastern shortwave trough -- which contributed to severe convective weather and intense gradient winds over parts of the central/eastern CONUS the last couple days -- was located over NY and PA, and will weaken as it crosses New England and moves south of NS today. The associated surface cold front was analyzed at 11z from an occlusion triple point over Atlantic waters south of New England, across extreme southeastern GA and northwestern FL, to the central Gulf. This front will move slowly southward across northern/central FL through the period. Isolated thunderstorms are possible along and just ahead of the front, especially during the diurnal heating period when low-level instability will be maximized. Despite favorable deep shear (effective-shear magnitudes around 45-55 kt in forecast soundings), veered warm-sector winds will limit both lift and storm-relative low-level flow. Midlevel lapse rates also will be weak. As such, severe potential appears too low and conditional for an outlook. In the West, non-severe convective potential will be influenced predominantly by a large mid/upper-level cyclone that covers the northeastern Pacific between the Gulf of Alaska and the coastal Pacific Northwest. This cyclone will move slowly southeastward through the period, with its eastern sector spreading inland, even as the 500-mb center remains just offshore prior to 12Z tomorrow. Accompanying cold midlevel air will steepen low/middle-level lapse rates, overlying Pacific moisture to contribute to isolated thunder potential in coastal areas. Large-scale left will spread inland across the northern Great Basin and Intermountain regions through the period, under a difluent left-exit region of a pronounced, wide upper-level jet streak with peak 250-mb flow of 150-170 kt. Associated cooling and deep-layer lift, amid weak but sufficient low/middle-level moisture, will contribute to sporadic inland thunderstorms. ...Edwards/Leitman.. 03/04/2023 $$ = = = To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM. --- SBBSecho 3.14-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .